A case of an infertile male with a small supernumerary marker chromosome negative for M-FISH and containing only heterochromatin.
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ABSTRACT:
SUBMITTER: Wang W
PROVIDER: S-EPMC2719068 | biostudies-other | 2009 May
REPOSITORIES: biostudies-other
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Project description:Chromosomes occupy specific distinct areas in the nucleus of the sperm cell that may be altered in males with disrupted spermatogenesis. Here, we present alterations in the positioning of the human chromosomes 15, 18, X and Y between spermatozoa with the small supernumerary marker chromosome (sSMC; sSMC(+)) and spermatozoa with normal chromosome complement (sSMC(-)), for the first time described in the same ejaculate of an infertile, phenotypically normal male patient. Using classical and confocal fluorescent microscopy, the nuclear colocalization of chromosomes 15 and sSMC was analyzed. The molecular cytogenetic characteristics of sSMC delineated the karyotype as 47,XY,+der(15)(pter->p11.2::q11.1->q11.2::p11.2->pter)mat. Analysis of meiotic segregation showed a 1:1 ratio of sSMC(+) to sSMC(-) spermatozoa, while evaluation of sperm aneuploidy status indicated an increased level of chromosome 13, 18, 21 and 22 disomy, up to 7 × (2.7 - 15.1). Sperm chromatin integrity assessment did not reveal any increase in deprotamination in the patient's sperm chromatin. Importantly, we found significant repositioning of chromosomes X and Y towards the nuclear periphery, where both chromosomes were localized in close proximity to the sSMC. This suggests the possible influence of sSMC/XY colocalization on meiotic chromosome division, resulting in abnormal chromosome segregation, and leading to male infertility in the patient.
| S-EPMC4663790 | biostudies-literature
Project description:Small supernumerary marker chromosomes (sSMCs) are defined as structurally abnormal chromosomes that may be detected pre- or postnataly in patients with developmental and/or mental retardation or infertility. sSMC on chromosome 15 accounts for the highest proportion of all sSMCs and may be detected in subfertile individuals. The present study reports the case of a male patient with oligoasthenoteratozoospermia and an sSMC. The sSMC was identified and characterized according to G-banding analysis, chromosomal microarray analysis (CMA) and fluorescence in situ hybridization (FISH) analysis. Chromosomal karyotype analysis suggested that the patient presented with 47,XY,+mar. CMA was used to characterize the sSMC, which revealed a 0.44-Mb microduplication in 6q25.3q26. Subsequently, FISH using centromere-specific probes for chromosomes 13/21, 14/22 and 15 was applied to identify the origin of the sSMC, which was finally determined to be inverted duplicated(15)(q11.2). It was hypothesized that heterochromatin in the sSMC is responsible for the patient's fertility problem. The presence of heterochromatin may disrupt regular meiosis, thereby affecting normal spermatogenesis. Impaired spermatogenesis in infertile males with an sSMC derived from chromosome 15 was also reviewed by searching published literature and the sSMC database (http://ssmc-tl.com/sSMC.html). For patients with low sperm parameters and complete absence of spermatozoa in the ejaculate, including infertile males with an sSMC with spermatozoa, intracytoplasmic sperm injection is considered as an effective assisted reproductive technique. It may be concluded that molecular cytogenetic techniques are critical tools for delineating sSMCs in infertile males and may be beneficial in identifying sSMC carriers to ensure they receive clinical genetic counseling.
| S-EPMC7086184 | biostudies-literature
Project description:Small supernumerary marker chromosomes (sSMCs), equal in size or smaller than chromosome 20 of the same metaphase, can hardly be identified through traditional banding technique. They are usually associated with intelligent disability, growth retardation, and infertility, but the genotype-phenotype correlations are still complicated for their complex origins and constitutions. Herein, we identified a 26-year-old Chinese infertile male who carried a mosaic sSMC and was diagnosed as severe oligospermia. The G-banding analysis initially described his karyotype as mos 47, XY, +mar[32]/46, XY[18]. The chromosomal microarray analysis results showed a 25.5 Mb gain in Yp11.31q11.23 and a 0.15 Mb loss in Yq12. Two SRY signals were discovered in the "seemingly" normal chromosome Y in both cell lines using SRY probe: one normal SRY was located on the distal tip of the short arm of chromosome Y while the other SRY was located on the terminal of long arm in the same chromosome Y. The sSMC(Y) was finally identified as der(Y) (pter ⟶ q11.23) (SRY-). To our knowledge, the chromosomal Y anomalies, SRY gene translocated from der(Y) (pter ⟶ q11.23) to qter of normal chromosome Y, were not reported before. Our findings indicated that the mosaic presence of sSMC(Y) may be the main cause of severe oligospermia although no other apparent abnormalities were observed in the proband. Further research on association between sSMC(Y) and spermatogenesis impairment should be investigated. It is recommended measures of traditional and molecular cytogenetic analysis should be taken to determine the origins and constitutions of sSMC so as to offer more appropriate genetic counseling for the infertile sSMC carriers.
| S-EPMC6885818 | biostudies-literature
Project description:Introduction: With only 39 reported cases in the literature, carriers of a small supernumerary marker chromosome (sSMC) derived from chromosome 11 represent an extremely rare cytogenomic condition. Methods: Herein, we present a review of reported sSMC(11), add 18 previously unpublished cases, and closely review eight cases classified as 'centromere-near partial trisomy 11' and a further four suited cases from DECIPHER. Results and discussion: Based on these data, we deduced the borders of the pericentric regions associated with clinical symptoms into a range of 2.63 and 0.96 Mb for chromosome 11 short (p) and long (q) arms, respectively. In addition, the minimal pericentric region of chromosome 11 without triplo-sensitive genes was narrowed to positions 47.68 and 60.52 Mb (GRCh37). Furthermore, there are apparent differences in the presentation of signs and symptoms in carriers of larger sSMCs derived from chromosome 11 when the partial trisomy is derived from different chromosome arms. However, the number of informative sSMC(11) cases remains low, with overlapping presentation between p- and q-arm-imbalances. In addition, uniparental disomy (UPD) of 'normal' chromosome 11 needs to be considered in the evaluation of sSMC(11) carriers, as imprinting may be an influencing factor, although no such cases have been reported. Comprehensively, prenatal sSMC(11) cases remain a diagnostic and prognostic challenge.
| S-EPMC10763568 | biostudies-literature
Project description:Small supernumerary marker chromosomes (sSMCs) are additional derivative chromosomes present in an otherwise numerically and structurally normal karyotype. They may derive from each of the 24 human chromosomes, and most contain a normal centromeric region with an alphoid sequence from a single chromosome. The majority of human chromosomes have a unique centromeric DNA-sequence enabling their indubitable characterization. However, chromosomes 14 and 22 share a common centromeric sequence D14/22Z1, and sSMCs with this DNA-stretch can derive from either chromosome. Euchromatin-carrying sSMCs(14 or 22) may be further characterized by molecular cytogenetics. However, in most diagnostic laboratories, heterochromatic sSMCs cannot be differentiated between chromosomes 14 or 22 derivation and are often reported as der(14 or 22). Still, heterochromatic sSMC(14 or 22) can be distinguished from each other using the D22Z4 probe (non-commercial) localized to 22p11.2. Herein, 355 sSMC(14 or 22) analyzed in the authors' laboratory during the last ~ 20 years are summarized to address the questions: (1) What are the true frequencies of chromosome 14- and chromosome 22- derived sSMCs within D14/22Z1-positive cases? (2) Does sub-characterization of sSMC(14) and sSMC(22) make a difference in routine diagnostics? These questions could be answered as follows: (ad 1) within the studied group of sSMCs ~ 40% are derived from chromosome 14 and ~ 60% from chromosome 22; (ad 2) the knowledge on exact sSMC origin can help to save costs in routine diagnostics; i.e. in a clinically abnormal person with sSMC(14) a test for uniparental disomy is indicated, which is not necessary if a chromosome 22 origin for the sSMC was determined.
| S-EPMC7908736 | biostudies-literature
Project description:BackgroundThis study aimed to evaluate the feasibility of chromosomal microarray analysis (CMA) in detecting the origin and structure of small supernumerary marker chromosomes (sSMCs) in prenatal and postnatal cases and to clarify sSMC-related genotype-phenotype correlations.ResultsThirty-three cases carrying sSMCs were identified by banding cytogenetics. Of these cases, twenty-nine were first characterized by CMA and only two by FISH. The remaining two cases were excluded for their refusal to accept further examination. The chromosomal origins of twenty-two cases were successfully identified, in which pathogenetic copy number variations (PCNVs) were found in sixteen cases, four cases showed variants of uncertain significance (VOUS), one case showed benign CNVs, and one case showed probable PCNVs. For the nine cases with negative CMA results, only one of them contained centromere heterochromatin likely due to its normal phenotype, whereas reasons for the remaining eight cases were uncertain. We also found that CMA results indicating pathogenic abnormalities further affect the rate of pregnancy termination.ConclusionsThis study showed that CMA combined with cytogenetic analysis is particularly effective in identifying sSMCs. However, in order to establish sSMC-related genotype-phenotype correlations, the inclusion of more sSMC cases will be necessary in future studies.
| S-EPMC6416931 | biostudies-literature
Project description:Supernumerary marker chromosome 15 (sSMC[15]) is the most frequent marker chromosome, and it is generally regarded as unimportant if it does not contain the Prader-Willi/Angelman syndrome critical region (PWACR). The clinical importance of the larger markers in association with the critical region is mentioned in almost all reports related to marker chromosome 15, and smaller markers are solely associated with minor dysmorphic features, azoospermia and recurrent miscarriages. However, these small sSMC(15)s without the PWACR may also determine a specific phenotype. A dysmorphic examination of an azoospermic patient in a genetics clinic was performed and was followed by a peripheral blood lymphocyte chromosomal analysis according to standard cytogenetic methods. Nucleolar region (NOR) banding, C-banding, fluorescence in situ hybridization and a molecular investigation of Y-microdeletions were also performed. The clinical evaluation identified dysmorphic features accompanied with azoospermia and severe 'Angle Class II, Division 1 Open Bite Deformity'. The molecular cytogenetic study revealed the small sSMC(15). In addition, a Y-microdeletion analysis showed that the azoospermia was not the result of a deletion. Although the presented case might represent a coincidental example of supernumerary marker 15 and mandibular anomaly association, the condition may also define a specific phenotype that may be more than azoospermia. This condition may be characterized by infertility, malar hypoplasia, mandibular anomaly, keloid formation and minor dysmorphic features.
| S-EPMC3735005 | biostudies-other
Project description:This study aimed to report a rare case of intermittent azoospermia and ring-like small supernumerary marker chromosomes (sSMCs). An infertile man was diagnosed with azoospermia presenting a normal male phenotype with complete masculinization. Karyotyping and polymerase chain reaction (PCR) were used to detect 16 sequence-tagged sites on the AZF subregions of the Y chromosome, and 115 candidate genes were screened for mutations. Mutations included single nucleotide variations, insertions, and deletions. Metaphase chromosomes were studied by standard trypsin-Giemsa banding; fluorescent in situ hybridization and PCR were performed to analyze specific Y chromosome regions; gene mutations were detected. Chromosomal analysis detected 117 metaphase cells; a mosaicism with marker 1 and marker 2 sSMCs in 2 metaphase cells (47, X, +mar1x2 karyotype), a mosaicism with marker 2 sSMCs in 14 metaphase cells (46, X, +mar2 karyotype), and a mosaicism with marker 1 sSMCs in 76 metaphase cells (46, X, +mar1 karyotype), coexisting with a 45,X cell line in the remaining 25 metaphase cells. PCR analysis showed the sY160 heterochromosome on the AZFc subregion was absent. Next-generation sequencing identified an asthenozoospermia-specific mutation in GAPDHS (rs2293681), and Sanger sequencing verified this mutation. This gene encodes a protein belonging to the glyceraldehyde-3-phosphate dehydrogenase family of enzymes that play an important role in carbohydrate metabolism. Like its somatic cell counterpart, this sperm-specific enzyme functions in a nicotinamide adenine dinucleotide-dependent manner to remove hydrogen and add phosphate to glyceraldehyde 3-phosphate to form 1,3-diphosphoglycerate. During spermiogenesis, this enzyme may play an important role in regulating the switch between different energy-producing pathways, and it is required for sperm motility and male fertility. A mosaic 46, X, +mar1[76]/45, X[25]/46, X, +mar2[14]/47, X, +mar1x2[2] karyotype could be the main explanation for the azoospermia/severe oligospermia, while the likely pathogenic GAPDHS intron mutation may contribute to the symptom of immotile sperms detected in the semen analysis.
| S-EPMC7180304 | biostudies-literature
Project description:Small supernumerary marker chromosomes (sSMCs) are a group of rare chromosomal anomalies, which pose challenges in the clinical practice of prenatal diagnosis and genetic counseling. This study enrolled an extended family with an underage male patient displaying infantile seizures, intellectual disability, and retarded speech and psychomotor function. A series of multiplatform genetic detections was conducted to explore the diagnostic variation. Whole exome sequencing (WES) and chromosomal microarray analysis (CMA) indicated a mosaic sSMC derived from the pericentromeric region of chromosome 8 in the patient, which was confirmed using cytogenetic methods. The proband and his mother, who carried this mosaic variant, exhibited strong phenotypic variability. We also ruled out the pathogenicity of a KDM5C variant by extended validation. Our results emphasized the capacity of WES to detect mosaic SMCs and the importance of mosaic ratios in the appearance and severity of symptomatic phenotypes.
| S-EPMC8272673 | biostudies-literature
Project description:Interpreting the clinical significance of small supernumerary marker chromosomes (sSMCs) in prenatal diagnosis is still an urgent problem in genetic counselling regarding the fate of a pregnancy. We present a case of prenatal diagnosis of mosaic sSMC(10) in a foetus with a normal phenotype. Comprehensive cytogenomic analyses by array-based comparative genomic hybridization (aCGH), sSMC microdissection with next-generation sequencing (NGS) of microdissected library, fluorescence in situ hybridization (FISH) with locus-specific and telomere-specific DNA probes and quantitative real-time PCR revealed that sSMC(10) had a ring structure and was derived from the pericentromeric region of chromosome 10 with involvement of the 10p11.21-p11.1 and 10q11.21-q11.23 at 1.243 Mb and 7.173 Mb in size, respectively. We observed a difference in the length of sSMC(10) between NGS data of the DNA library derived from a single copy of sSMC(10), and aCGH results that may indicate instability and structural mosaicism for ring chromosomes in foetal cells. The presence of a 9 Mb euchromatin region in the analysed sSMC(10) did not lead to clinical manifestations, and a healthy girl was born at term. We suggest that the ring structure of sSMCs could influence sSMC manifestations and should be taken into account in genetic counselling during prenatal diagnosis.
| S-EPMC8391546 | biostudies-literature